OTTFFSSE

Puzzle

What letter follows:

$\text {OTTFFSSE} \ldots$

?

Solution

$\text N$

They are the initial letters of the first few natural numbers:

$\text {one, two, three, four, five, six, seven, eight, nine} \ldots$

Sources

• 1980: Angela Dunn: Mathematical Bafflers (revised ed.) ... (next): Preface to the Dover Edition